SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40f8c5f515e07b8764c5de84eb91c482e56d1173db4851cafa8e6a760b33e5a4' 
  AND token = '1sy+SPScplJHSymEh4X4YKwmP5Z5W5hI71AGhpP1W9Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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