SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2706316ddddce8bbf6e011043fca3f4587310dc7fe3e506cb31f839d2322fa32' 
  AND token = 'vVmudGHBBQA7aSVz0AdywioMKNdNLufY8Usae7TiYrs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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