SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a578924e760f0402ad741a94f01772285bd2025570d0a287b33ee2cdb003e049' 
  AND token = 'rP7X8CecHGckJMEEm3pO7dJByUGba0ulYxxqEI5fe9Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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