SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '8f6871177be5e27eb05f40c4e35ae7552057d6a909062471749f1f418f7b50ff' 
  AND token = '68DXcuwMBsTi+mXVzQmo2NfB+UsTrYrjWH7FgYBCJ0Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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