SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '8f506a039de987be04de4a9b2383759acece6aa4b98e2a9b901423076c5ffba8' 
  AND token = '61RNbrZW6yG+sK/FjVss4YwpBxMYmhcHdynlVd+tCJE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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