SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f1dc1b065ee6d4ab165b568b1fd4156ddd7e04a83c360072c9c4bac28f6db3f' 
  AND token = 'Ru6DPRksLV/rNJlFGtq+jbmFak1Lo/oZ+Vz1TvCeh/Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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