SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44157fd44faefc8026654d9177e8c9451a40869a8a19e439253fbed131a451d1' 
  AND token = '1plvmVaB9z7PvW6+BAYHGIgxTArnPswdGKXt2vO6ndU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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