SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f49c241d94257dcada04e709ee1ffe1b484b24a4507ed9605bd6ffe6deb6719' 
  AND token = '6zUmNZ15aF4OAQUDEpwNsKNhKsEMDyHDiLJoNZC5fkU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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