SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ab6f069e4b6e4c75db86a4bc39fd3596042ec321b509517884feaa68042ce6c' 
  AND token = '1bOerI17wgXWca2v988vBPdm3jUfTfkJIa/0oWLOKp8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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