SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2cdb7e760ec35cca0258effef6da2705c5c095bdc08e8617245b004152794b3f' 
  AND token = 'fbO1yAhznJcMaszoXqGaNixKF/ciHv2u6/7b2tDt310=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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