SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ec68d9fec5bdaeae706534f4d74f59aadf233eaa826f295e4fa1d2a289360a48' 
  AND token = '6y8dfFne2Ggx9pqOEvQLhlOcn90sqPVcPn6/mf7Hj+o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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