SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f435a08c650df65d1dc943ebaef50f2ace031b22340408a2030b09208b01f58' 
  AND token = 'v/XnkGhTBBpLHC68/t2rPfoD/brwk1gOkGhGJeaLOBQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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