SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cea75f392bc049bdb92121c3ffdb778723150572dc539ae7d7399f6fa66ecd55' 
  AND token = 'gYnjvzY4eA160OyCO2Uxd/vmqyJDeNNwcmUeqPBVjs0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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