SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a635d78cabe439a3a0cea9640955ca1fd5296ad6e9609e5b1c2db5fc9d3874d6' 
  AND token = 'KwZ8SfB9FfipCWkt7jbD7/g3b88oZ2TAWYOgzPav3O0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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