SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '87b959f97744f19ad483e41cb1dc39c1135e62ffbd833b752441e428197b6594' 
  AND token = 't8IlIUe+PKk0inrMA8WwUJPBtJYSOt/Z3RaI1jariw0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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