SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '79e159a99247eed1ab114dcb40e8598e6552325f37ba206b326288545f6c7724' 
  AND token = 'FIrtIgkb5E+QQL2IYz3dtuBe9vTAk/FKDLcQkOJGXMo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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