SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab0c6a5bcf3bd90af19af8117486ad75639746b66609724fe34793779ad91a95' 
  AND token = 'RcrqfBgWf9PBuFl+MLLYto/yDPFph/h3dZYgzAByuME=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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