SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '534111610e7384379ba141351256f89319c3cff6018d6fd9393dd8820b81018d' 
  AND token = '0jMYXAZP8CKr/YgZLDSib+rcDtkIV8wwwRccPnkR82I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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