SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '4e87f3ccb516f4cb25f33911751ffbe38cfe12189e979e530585941def82db17' 
  AND token = 'Uafh1QY1vPbsLreFExa1T33bpgbfOZY015f6hxSMjHo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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