SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff2646f8ada411acaa8ada437b39c68cce0331fe544b84c66124d8eac22a3616' 
  AND token = 'Wwwib5eIvri1678+NTo8P//kkVdB4KgARpWCHKHsyX4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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