SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30103d28853e765f95c93a9a7df179268368750bd644c8f1b764f4ce1d1acb62' 
  AND token = '04QrML7wDxOpw/M/sanD6g7zsT9GU7jfl9PVDW6mYP8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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