SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f0fe7200adbc529dea2fb73760a10a56dcc251cb77bfe5520e5cdc4a3565c7c' 
  AND token = 'DI3MNn9+2UDrVKsPfSdzm/X5yU3KRddvsGHU425d5EU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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