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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90a54c9dd2e73b2afe1d25098572eab25d6b6caf4f655c54e1ff2d5c23722777' 
  AND token = 'C1SAFWKFKZB94IiV0Nw2O2ePyrVoiqf42iy87BoL8WM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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