SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b74ac783b46d0ce4979011bd5170d9d25c449b30ebcf9872e184a7ebe416002f' 
  AND token = '2uWhzbgoH5x0Ztr45VRxElR09NgUlj69rf4pjhAuAZw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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