SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2ed023379232e68dd76e3be64c98f94aede53fd7b9e6d734760f96b361a0a58' 
  AND token = 'Q2BgaByt7dGjYh/z72s0G6xPmTW2MlVxrLYM7juQ+bQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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