SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '36ae57ebcceb3c983913d32565c987967b8bf094b8b742efd297dd2994d1d2cf' 
  AND token = 'v84Yyhn+PJNrY1ToWcHI53a8hNQfhOgXmLwILIawUh0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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