SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '73ca0d55e8f0c2e70b483ad734994ab1b7c510d37cbcc1c4995bd003c07bce7a' 
  AND token = 'j0VVzChHk+YzqRrm9L9FzZZif0XrHz37aEGPxqZwovo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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