SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8967f423526b5fd04ce5e8848f93125509c0bd6022811f1665e6d8866934226' 
  AND token = '37HpZmYXAZ+JLN2OF6sVtFAsn71tdMQpQ3jznlvfdJM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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