SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84a5811089f5a376bf7ef9403fab02ec9b4a9f50902ab038403be4281bf20e1b' 
  AND token = 'a6TnP+iYFoOelwKwCYm8gYdQEfGgk7Z8tU1J2LLtNuM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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