SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b666dc4dd78afce3925e0fa3552d3cc1862559477a79d7a1b95adc5963831751' 
  AND token = 'GlTCwTUz7dpFifZoUIUSBGvQ6QFRHxxVpUG601Lj/3M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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