SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '494c4a5f0f1eaabd30dd90ccbbb026134208e30d03d348a694e0dec6b855cc10' 
  AND token = 'QS/whH5ZtW0drAOTuyk7gR9ehoq8e3Vt+l4VpMg/ty8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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