SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0047743598ead85adb883140b8073971cdd9a4eb438905069db65422d876243e' 
  AND token = 'P8MVixU2IRTfSTEyGqSsL5NIqrwdZNkPvxWLgXkub7Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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