SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'd175cda6f9791147cb800d1fcf68207edfc072678949759108f406d04035e6bd' 
  AND token = 'VlnKZ4QqRZqrbCbIv9n8VZyVaf78edSYmOZOgJlmj5g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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