SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61724c6e7054b1d50052a8312347053e987c97861c92ad70935862d78b6f2812' 
  AND token = 'P/Ku9yBjPoJFtwXnCp7QfyW3OJ/UjyoyHNWGkBrLsIo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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