SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '76b8242ddba157d34be1e22bae1b5c1e4653dbc686ae24db9f19ddfe2e456942' 
  AND token = 'Ax6+E7hiKfoK+P3zThKZixYXkRMGgJtY11JesVDhjtk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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