SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98cbe92e844214b8b944e785338e8c185e25575525091fc0614b3967feadb9a2' 
  AND token = 'tqOl42uXuDOxAfJGsUcik2WXbFaOzXxzG5wtYlBNiNY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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