SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8eda6c9a3e6953945668eac3e4d775d22deb0768ba411bc28a8b0f65baea469' 
  AND token = 'qWjumE/ndB3CDAgza49amoza5tyPDLY+9T3HPdrxIzU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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