SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5544347a762be3edd7fb86efd971083cb9815412194c7fec00be87389514fa61' 
  AND token = '95QKLhrwRRx24qdBYXQWemvdgpKUEiczKoL+5fb3fXM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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