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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '80b735548522961cbe11409917a83ebbbf15e8701b5251140e72847564cb37db' 
  AND token = 'r0zv1Qe7egcWQ4pBXhhR80ka6b33+/HEK6UkCi9+2nQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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