SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '493941b3e212ca276217fc48469e8796110bc9becd2bea0a8b3a888fde214c66' 
  AND token = 'KWFfIysU3DwjZ6oQw+eNvjP7LsZjNAS6IodXoBLcDH4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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