SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3ce5114100dd2e0880dda2afe513bfd60d38bdf671601b42aabe26b7229e314' 
  AND token = 'a7hTzYlOTsOPtK/jihwX0T7Vphz3dEIQF8dZIOSp2rY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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