SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1bdd20a2eabff2444c751a42667794ef84f848d1afc131c6a81d8b18f1d92f13' 
  AND token = 'IScti2Wt63mXH51+665Wic7aVVeOFeBjEyzzt3dvass=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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