SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6642008f73f659fa9548b89d743f242152118e1fcee1475721f0bf13fcc3bf9a' 
  AND token = 'Wa5mr8i/zaStaz0JkEi9r3v4IxHOGz+nU9BYCDpOCbM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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