SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '326567f10ba5a5d55acfee2fa0c40fc3669312fff26d1c504b892f94e72a133f' 
  AND token = 'R5xAcw3bZGn7kDicMfCAnj1v3jn99Zb1FFSOQm+LalE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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