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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26fe231f34d0236632763c1e249862e64b326fb7630ed5c9f65522f31db45822' 
  AND token = '5BVZs+ajSE/Cnc+40ERXYsnI8SRdpGusiEq2hDmPUuY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}