SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9ac18503f1699d36b40a6b2705e12dfc8586a9a13502d0097fd33ea59096879' 
  AND token = 'ygnyqztmKAZNNdaZw+b5v49p6gUMfMrIWEkIyGnw7sw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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