SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '4e033734a55c6585aad20e4010820e8cb694fb54e3168ad80554a732739f3c3f' 
  AND token = 'BU1qaIXFdPnd2C8tC6NOHRk+3+O1L3Alsn0cOB01FM8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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