SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '07841c236e1d788f7ce2511474156cac43d6f020e15cf24c1471365ec9823f68' 
  AND token = 'h6+x+/Hr6gisEhG2zCD9ryPj3Btp8lEbDlpGgJ79qXU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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