SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ead69d61f6bc20393146e1694a67228f16b7d2ce6fc22e24517bc3ad9713d558' 
  AND token = '2WDOypXhoyXpEYDNd4cgAnzv4DQiQQxLqFsfEVB8PbA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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