SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '734cada4b95a982d4d1a467a5c6392db20e5f6b89bf898f9140de93f57142f26' 
  AND token = '5mlmHkAP1qD82KibsCANh6HDOjVJZLpgEQFDDN+M8sA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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