SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'cfd259381ac4501e32ac88d01eb799c35b7835c66dbcc67f0d4727ae0d0e3bb1' 
  AND token = 'pMBeH2XtEBNxjyIVuYpSFn9NLQQdbl3mt3B1l2ZFt58=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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