SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1eefb1c099ee68a210f430b1346d939dbaad86403777ed22feae9531e50b4161' 
  AND token = 'qeVYB2nJSSqNbc+tjg6//pr2IgF6LTQGKu/QCsX4PBc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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