SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e1db9fd9ea3f467064178f06e1baec9d781d7c9d3c96c49e2be3aa937d478b6' 
  AND token = '7Kz84nUOgWQHXASssWt3dIgfbf1cdK/rwkPG4hj4Gq8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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