SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '892742e8c2298b1edc9effdbd05ab46443180b2020fb70aa93dbf9187c608cc4' 
  AND token = 'rfeti4sG6ovxzMhHo2orYNIbWvmtJjyiEcNNq/62QVs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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