SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '247de548f913242cdc7e67e951da077604548874dbc70b3ce41ad8b12049a00f' 
  AND token = 'TowJ9LGhMOJB3QHp4ZAVg2r1L4LsjxK5tf/HDQTNo+4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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