SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b8ea1481b7b91addbaba4f2ac328cd86eb43b90d69f0d98ca29748de1d2cdd4' 
  AND token = 'OIHUntSHOZSotMFyESD3fYg2sc3SxIVP7RzWgPThuss=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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