SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9aa8bfaa5dbbf8d97c8c9826d637442fe5caff3208ec35bb0a64f7c91e465a9d' 
  AND token = 'py/lnuAxW9GeknZ/5gY0W07qJgveY2s6XoEjWKXRqCE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}