SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e23ac9d3079156b48f6b5f826e528b6fc4938abaf5117a276c10e96c4ebdccbd' 
  AND token = 'cjOQwp93RthJyeHJ69P5XjkF6mf7p/K3L7t4+4F6QEw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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