SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '408d8358590f2e6172018a3b1863fbd236ef4618e6a5316bbdca0ab1ac579c57' 
  AND token = 'Xk8YKJrDeRMkaXnP2B4caY/NlHQr3r7OJEnJ1I7AoLE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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