SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03745901625fec85105e1ea2dd23adec785775f67a433c8dadea64e42ff629bc' 
  AND token = '3nqRfytlF/1JvH7X0oubHqjNJhiXPHUZltqq9OJw+YI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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