SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ef9806528d273d7087e3032afd558f024ee7fa6aebdae1cec024febb16c9898' 
  AND token = 'MGAwLX1yeXOyKv/xXNnV6hOkRLD6LN5eoChBcWNmYns=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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