SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef7ebfaf83cbcad39f76c4cb2c519c41685512b2aca6ef988273bc51cdefd777' 
  AND token = 'wF6R0dMulGTmop9vwdkkrfOiKssad7TZHvojyMMJ/MU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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