SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78bcbea22e740b1ce73ff530aab9ddc411ba611c29e291261b243f659b378e7d' 
  AND token = '/8gjhf1a3eK8mCknOTSYL4+E7q4XOhhu7BsAjBz5AXw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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