SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d46e187df59625bd67d953488b1029b382ee7bfc1913d51d0d6abd78535deca' 
  AND token = 'YKYsHUKnEmgOm7rJboNh7HvHZ2TOQUJBCvAupGaDM4g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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