SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5449fa57e54c5dc28760d9a7c6834ca01f2fece6245e69e6ca72871bc6fefb7d' 
  AND token = '1OiZQLx1JAYMpToY/8Tjjy0TI6GgOVgmmeS1CZqJBw4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}