SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f3f8390ce1488388a240ae6f31f199d52156b5e4b8b7d2bbb5336f4ffd5f61d' 
  AND token = 'Z2RuFiBnCSkFhMPBoBiE/N3/KdBjxic1dLQ+j94qqVI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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