SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '181088b8d368d0acc1c2e384af0897f5f8b5eadf330570ee4f418fc307963a55' 
  AND token = '8KItIYN77tVauwQaUS0OZga6gADo9+FuiBt4QiReKNQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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