SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '778dae971fb7c9ed67a8e90802cd1a5e40a0ce67755b3034059eb4af079e4d1a' 
  AND token = '8vRzrpWEG5LAYt1E2dCXAxLXiED0bRu+29Hg3VdW/zw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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