SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70856ddb3d263a4a1e42f7997ff3d5ec1b6d55494f1b24c8ee487195e4bddcc3' 
  AND token = 'p5Eoj2GUvcJ6GSUN+Iedz/Duen0JM7thv4shLFEEal4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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