SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ffbbc100edd0bdb3df240972758175e65994190731fb0d87371fb281845f833e' 
  AND token = 'ahfw3JpBk1crwfg9JYVvV+g300pWLwD4+CnQdjLcl8s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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