SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd120f7a5bbbf5d2429b5ddca16fe38f1d0fa36ffea21d2faa78cadfa52b91dd4' 
  AND token = 'JS0kKgrCvcf2/TZpsMjAia1IyQIhhtjHuDj/DAk55TM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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