SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b473dae1975be0dc2f7166471765c603b91cc5527bd6aedb04e27273c861d681' 
  AND token = 'l97VqXXqFfhlUCAKRG6xboVrOPyoDnOQESTwoKWKDu8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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