SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c2e288df5ca553ccd309b493c04f3754c508ad675aa7507f672995ef9c1651d' 
  AND token = '3WleqblTqsuRl4MYh4QPz9fZh4n7wIjhnfJwFH1/2WY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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