SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3752dc3ed944ca46b430bc9cbcac80fd43f16df6cd094f9735d00ed5183baf84' 
  AND token = 'GjdyajDPbyrQL3F4xdn15ZxEbwCMQfQXqiwXbyRyQFk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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