SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '185f95c04db4f767c9ee32d0c3d4731b1985bd26115c23b7d36e70f43bce2d97' 
  AND token = 'eHewh8vih6MTwJRNLgYtOeXAJUM1qsfxM2XQiYzhGjM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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