SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0d08c38874252e8192c349e1b0e815d0c20834539642b6e8a9a4c624aca3576' 
  AND token = '/ZWnBKh5HXsEgb+IvNFHUgq/4vjYcGKRnw92KjoA9ls=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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