SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '29444ac36539f42b83eb0984300d8eab4679e6bc92fd6c657e4ac7094bf4691a' 
  AND token = 'VvEqicT3v3d31XFVOKDN3wv3cuRIc7bcNbnWGmBp/aE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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