SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa686021807968b434670f91cd081b53a5cbe9f9dae2b0b08adb993254657794' 
  AND token = 'Mik6rIgJ6CbPA/ap6tM1p63yvQEQdiY2gKHYRYPixAs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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